Syrian opposition coordinator Riad Hijab defended his body’s decision to walk out of peace talks in Geneva and criticized U.N. envoy Staffan de Mistura over the rise in violence, during a high level EU visit to the Turkish border province.

Hijab’s public criticism of de Mistura, who must be seen as neutral while trying to negotiate peace in Syria, highlights the tensions and fragility of a peace process which has limped on despite the opposition declaring a “pause” in talks with nearly all of its delegation leaving Geneva.

“For two years, Mr de Mistura was appointed in his task as a U.N. envoy and during this period the killing was increased or doubled in Syria and also the number of villages and areas that were under siege also increased where is Mr De Mistura and his team,” Hijab told reporters in Gaziantep where he was visiting a refugee camp alongside German Chancellor Angela Merkel and Prime Minister Ahmet Davutoglu.

Despite a breakdown in a truce, the failure of which Hijab said must prompt a reevaluation by world powers, and signs that both sides are gearing up to escalate the five-year-old civil war, De Mistura vowed to plough on with peace talks. Some diplomats called on de Mistura to exert pressure to make the talks successful.

On Saturday Hijab, a former prime minister, defended the opposition’s decision to suspend the talks:

“We put our participation in the negotiations on hold to respect the Syrian blood that is shed under strike from the regime and its allies and to respect the Syrians who are killed of hunger following the siege and to respect Syrians who are killed under torture.”

(Reporting by Yesim Dikmen and Muath Freij, Writing by Dasha Afanasieva, editing by David Evans)